In a system including an internal combustion engine (e.g., a vehicle), a motor for making an individual constructional member thereof operate may be placed therein.
For example, Japanese Patent Application Laid-Open (kokai) No. 2001-78480 discloses an electrically-driven power steering apparatus. In this electrically-driven power steering apparatus, a direct-current motor for assisting to steer front wheels is comprised.
In addition, Japanese Patent Application Laid-Open (kokai) No. 2004-339984 discloses a compression ratio-changing mechanism capable of changing a compression ratio by moving a cylinder block in a direction of an axis of a cylinder relatively to a lowercase (crankcase). In this compression ratio-changing mechanism, a servo motor is used as a source of power for moving said cylinder block.
Further, Japanese Patent Application Laid-Open (kokai) No. 2008-50956 discloses a valve timing-adjusting apparatus for adjusting a valve timing by rotationally driving an electrically-driven motor. This valve timing-adjusting apparatus comprises an electrically-driven motor such as a brushless motor or the like.
As disclosed in Japanese Patent Application Laid-Open (kokai) No. 2001-78480 or Japanese Patent Application Laid-Open (kokai) No. 2008-50956, this type of motor is electrically connected with a driver circuit. In addition, this driver circuit is electrically connected with a control circuit. Then, said control circuit provides said driver circuit with a control signal, and thereby the movement of said motor is controlled.